Category: Bug of the Week

Bug o’the Week – Little Yellow Butterfly

Bug o’the Week
by Kate Redmond

Little Yellow Butterfly

Howdy, BugFans,

When the BugLady was on the trail recently, a small, yellow butterfly flew by, just above the ground.  It was noticeably smaller than the ubiquitous Orange and Clouded Sulphurs, but it zipped out of sight pretty fast.  Mike Reese, host of the excellent Wisconsin Butterflies website (https://wisconsinbutterflies.org/) describes similar experiences “It has not been the easiest butterfly for me to observe. I have seen this butterfly in central Wisconsin several years and have attempted to photograph it. All the individuals I saw took off on a beeline for other areas, dancing calmly but surely away from me, never to be seen again.”  Fortunately, the BugLady’s butterfly turned around, came back, and posed nicely.

It was a Little Yellow/Little Sulphur/Lisa Yellow (Pyristia lisa) (formerly Eurema lisa).  Like the larger Sulphurs and the “Whites,” it’s in the family Pieridae.  Its wingspread measures 1 ¼” to 1 ¾” (females are slightly larger than males, but otherwise males and females are very similar), and there are pale and dark forms, depending on the time of summer https://bugguide.net/node/view/1752987/bgimage, https://bugguide.net/node/view/898574/bgimage.  The BugLady’s butterfly snapped its wings shut immediately; here’s one with wings open https://bugguide.net/node/view/1184957/bgimage

Little Yellows are southern butterflies, abundant in grasslands, open areas and along woodland and road edges and railroad tracks as far south as Central America and Costa Rica, but they migrate north in summer and are found from the Great Plains as far west as New Mexico and South Dakota, to the Atlantic Coast as far north as Canada.  Their numbers in Wisconsin vary from year to year, and they may persist into October here, but the final generation of the summer turns around and heads back south again. 

Males keep an eye out for females, and when they see one, they court by touching her with their legs and wings.  The female responds by spreading her antennae so she can sense his pheromones.  If she’s not interested, she flutters her wings or departs; if she is – https://bugguide.net/node/view/2299141/bgimage.

She lays her eggs on the midveins of the leaves of a host plant, and when the eggs hatch, the larvae feed on the tender leaf tissue between the veins, resting along the midrib (nice series of pictures https://bugguide.net/node/view/1036429).  Adults live a brief 10 days.   

Little Yellows may produce five generations in their southern breeding range, and those that reach Wisconsin and beyond will breed if they can find host plants, but they are too sensitive to the cold to survive winters above 40 degrees north latitude (Philadelphia, PA to Columbus, OH to Boulder, CO).

Most sources only list a few caterpillar host plants in the Pea/Legume family, specifically Partridge Pea, Wild Senna, and Mimosa strigulosa, a small mimosa shrub.  Ebner, in his Butterflies of Wisconsin (1970), writes that clovers in the genus Trifolium are undoubtedly used as host plants by the Wisconsin populations.  The butterflies nectar on aster and goldenrod, and crowds of males gather at the edge of puddles to sip minerals from the damp earth https://bugguide.net/node/view/432629/bgimage.  Little Yellows are preyed on by crab spiders and ambush bugs and in the south, native praying mantises.

Little Yellows are small but mighty – they’re famous for mass migrations that take them far from home.  In 1874, Samuel Scudder described a swarm that reached the Bermuda Islands, “Early in the morning, several persons living on the north side of the island perceived, as they thought, a cloud coming over from the northwest, which drew nearer and nearer to shore, on reaching which it divided into two parts, one of which went eastward and the other westward, gradually falling upon the land.  They were not long in ascertaining that what they had taken for a cloud was an immense concourse of small yellow butterflies, which flitted about all the open, grassy surfaces in a lazy manner, as if fatigued after their long voyage over the deep.  Fishermen out near the reefs, some miles to the north of the islands very early that morning, stated that numbers of these insects fell upon their boats, literally covering them.” 

Magic.

Kate Redmond, The BugLady

Bug of the Week archives:
http://uwm.edu/field-station/category/bug-of-the-week/

Bug o’the Week – Rough Stink Bug

Bug o’the Week
by Kate Redmond

Rough Stink Bug

Greetings, BugFans,

The BugLady has a thing for stink bugs.  They’re like bumble bees and water lilies – she can’t walk past one without taking its picture.  She especially likes stink bugs in the genus Brochymena, the Rough stink bugs, which look like walking fossils.  But before we talk about the Brochymena, which have made a few brief appearances in BOTW, here’s a brief Stink Bug 101:

Stink bugs are in the family Pentatomidae, which means “five sections” and refers to the number of segments in the antennae.  In the UK, they’re called shield bugs, a name that is applied here casually to members of the Pentatomidae, and more specifically to members of a different family.  About 220 of the globe’s 5,000 stink bug species live in North America.

“Stink bug” because they are chemically defended – when alarmed, they can release a lingering odor that may be unpleasant (or not), noxious, or even toxic (think “cyanide”).  As a defense against predators, the odor is imperfect.  Most birds have no sense of smell, but a smaller predator that got a face full of chemical spray would be deterred, and some parasitic wasps and flies actually locate stink bugs by their odor. . 

And, of course, common names being what they are, the name can and is applied to any unrelated insect that has an odor.

Many stink bugs are plant feeders (some damage agricultural crops), and others are carnivores that help to control unwanted insects.  And some, in cuisines around the world, are prized for the spiciness they add to a dish.  All feed by poking their piercing-sucking mouthparts into their food of choice and injecting a saliva that predigests tissue so it can be siphoned up.

Most stink bugs come in utilitarian greens, grays, or browns, but some come in pretty flashy colors https://bugguide.net/node/view/531728/bgpage, especially as nymphs https://bugguide.net/node/view/344542/bgpage.

A few species of stink bugs exhibit maternal care – https://bugguide.net/node/view/1329274/bgimage.   

ROUGH/TREE/ARBOREAL STINK BUGS – Brochymena – are one genus (with 17 species) of one tribe (Halvini) of one subfamily (Pentatominae) of the stink bug family.  Based on images they’ve received from their community, bugguide.net shows the Brochymena occurring from sea to shining sea, except North Dakota and Manitoba, and their range extends south into Panama.  They’re typically found on trees and shrubs.   

They’re typically found on trees and shrubs, but their cryptic colors and textures can make them difficult to find because they look like a bit of bark or lichen on six legs.  At about 5/8”, they’re large for stink bugs. 

For the Brochymena, everything was going swimmingly until 1998, when a new stink bug came to town.  It was the Brown marmorated stink bug https://bugguide.net/node/view/2232265/bgimage, which is a huge pest in orchards and agricultural fields and, in the winter, in homes.  The two look similar – the BMSB has wide pale bands on its antennae and one white band on its hind legs; while the Brochymena have two white bands on their hind legs, a protruding, square/pointy face with antennae noticeably in front of their eyes, and toothed “shoulder pads” that look like a bit of cog wheel.  If you see a lot of them, they’re BMSBs. 

There’s some discussion about their diet.  Bugguide.net says that they are “Phytophagous [plant-eating] (some reports of predation).”  They’re known to feed on the sap and leaves and seeds of many species of trees and shrubs including ash, willow, and box elder, with brief, opportunistic forays into carnivory.  Unlike many other species of stink bug, they’re not considered harmful, and because they’re not considered pests, they haven’t been exhaustively studied.  Other sources say that their forays into carnivory are more than occasional, and that they eat caterpillars, leaf beetle larvae, aphids, and other soft-bodied insects that they come across. 

A Rough stink bug’s “stink” – said by one source to smell like maraschino cherries, and by another, like almonds – may not deter ants, tachinid flies, sand wasps, and a variety of birds (especially vireos, says one source).  Eric Eaton, in his Bug Eric blog, writes that “Given their cryptic nature, it amazes me that any other creature could find them and make a meal out of them.”  He continues, “Feather-legged flies in the genus Trichopoda glue their eggs to the top of the stink bug’s body, where the insect cannot reach to groom them off.  The fly larva that hatches bores through the exoskeleton of the host and feeds as an internal parasite, usually killing the bug eventually.” 

Adult Brochymena overwinter, sheltered in leaf litter, mulch, bark crevices or logs (some pick stacks of firewood, and are then brought inside in winter), and they’re sometimes seen out and about on warm winter days.  They emerge to mate in late spring, and females lay eggs in clusters of 10 to 20 on twigs.  Adults die by the end of June, and nymphs are found throughout summer.  There’s only one brood a year.

Eggs
Nymphs

Isn’t this “probably unnamed” Arizona species a beauty https://bugguide.net/node/view/2355448/bgpage!

Kate Redmond, The BugLady

Bug of the Week archives:
http://uwm.edu/field-station/category/bug-of-the-week/

Bug o’the Week – The End of Summer

Bug o’the Week
by Kate Redmond

The End of Summer

Howdy, BugFans,

We’ve arrived at the final act in this summer’s insect drama – a drama played out over the months by an ever-changing cast of characters.  Some are regulars, with successive generations appearing in multiple acts throughout the season, while others step in for only one act of the play.  Here are some of the actors that appeared on stage after mid-August.

DARNER WITH SPIDER – well, the darner migration was nothing short of magical this year, and then it was over.  And then it restarted – lots of Common Green Darners in the air on September 19 and 20, along with a bunch of Black Saddlebags.  They’re heading south along the lakeshore, aiming for the Gulf States, but they don’t all make it.  The BugLady’s guess is that this one was perched in the grass, and when it took off, it ran into the web of an orbweaver.  It messed up the web, but because it wasn’t flying at full power, the spider was able to snag it.  THANKS to the family that located this tableaux along the trail and pointed the BugLady at it.

TIGER SWALLOWTAIL – perfection on the wing, but far too few of them this summer.

GOLD-MARKED THREAD-WAISTED WASPS (Eremnophila) put the “thread” in the Thread-waisted wasp family (Sphecidae).  They’re solitary wasps that dig single-celled egg chambers in the ground and provision them with caterpillars of sphinx or owlet moths (and the odd of skipper butterfly caterpillar).  Her long legs allow her to straddle a larger caterpillar and walk it back to her nest https://bugguide.net/node/view/1408944/bgimage.  She keeps her strength up by sipping carb-rich flower nectar.

RED-LEGGED GRASSHOPPERS making more Red-legged grasshoppers.  ‘Tis the season.  

GRAY HAIRSTREAKS are listed as the most common hairstreak in North America (because their caterpillars are “catholic” eaters that feed on about 200 different plants), but they’re not common in Wisconsin.  

Fun facts about Gray Hairstreaks:

  1. The point of the eyespot and the “tail” is to make the butterfly’s rear end look like a front end, with eye and “antenna,” thus confusing predators;
  2. Gray hairstreak caterpillars are tended by ants in return for honeydew (produced, of course, in the caterpillar’s “honey gland”);
  3. Both the caterpillar and the pupa produce sound.

TREE CRICKET – the voice of the prairie in late summer and early fall.  This one is (probably) in the Oecanthus nigricornis group, maybe the Forbes tree cricket https://www.listeningtoinsects.com/tree-cricket-introduction

BIG SAND TIGER BEETLES are all about sand.  Their eggs are buried in the sand; their larvae https://bugguide.net/node/view/1277687/bgimage dig long tunnels in the sand and then pop out when unwary insects and spiders wander by.  At up to six feet long, the tunnel extends below the frost line and allows them to survive the winter.  Adults stand “on tiptoe” (stilting) to raise themselves incrementally higher off the hot sand.  Not surprisingly, Tiger beetles have fan clubs.

FIERY SKIPPER – these beautiful, inch-long, golden butterflies aren’t from around here, though they regularly visit God’s Country and beyond.  Their usual range is southern and even tropical, and they move north in mid-summer and produce a brood here, but it’s too cold for them to overwinter (for now).  They’ve made it to Hawaii and are unwelcome there, because their caterpillars feed on grasses. 

EUROPEAN PAPER WASPS are buzzing around the hawk tower these warm, sunny days, so the BugLady has to look sharp before she puts her hands on the railings.  Fortunately, they are jumpy wasps that usually spot her before she gets too close.  They arrived on the East Coast 40 or 50 years ago and have spread across the northern US and Canada.  They catch, masticate, and regurgitate caterpillars and other small insects for their larvae.  The lovely gold legs and antennae separate them from our common Northern paper wasp.

Fun facts about European paper wasps:

1)    The brighter the coloration of a female European paper wasp, the more toxic her sting is;

2)    Females with more spots on their faces are dominant.

FAMILIAR BLUETS – Big and startlingly blue, Familiar Bluets are one of the last damselflies on the scene.  (‘Tis the season.)

Caterpillars of VIRGINIAN TIGER MOTHS are also known as Yellow wooly bears or Yellow bear caterpillars (though they come in white, yellow, caramel, and rusty colors, and here’s a pink one https://bugguide.net/node/view/1728143/bgimage).  They’re food generalists, and so are all over the place (not just in Virginia).  Although some people are sensitive to their hairs, the hairs are not poisonous.  Adults are spectacularly white https://bugguide.net/node/view/1984450/bgimage, but when they are alarmed, they curl their abdomen to flash a startling orange https://bugguide.net/node/view/2329153/bgimage.   

NURSERYWEB SPIDERS carry their egg sac around in their jaws (wolf spiders carry theirs aft) and when the eggs are close to hatching, she creates a loose “nursery web,” installs the egg sac in it (hers was on the underside of the leaf), and then guards it until the eggs hatch and the spiderlings have molted once.  No help from Dad – if she doesn’t eat him (sexual cannibalism – an important nutrient booster) (he wraps her legs with silk during courtship to try to prevent this), he leaves to pursue other relationships.  He gives her a “nuptial gift” of a silk-wrapped prey item at the start of courtship so that she will think well of him, but after he has immobilized her and exchanged bodily fluids, he takes the gift with him when he goes. 

CRANE FLY – the “Old Wives” really got it wrong about Crane flies.  Though they’re also called “mosquito hawks,” they do not eat mosquitos (or any meat of any kind).  They do not bite anything at all, but they’re reputed to be the “most venomous insects in the world.”  The confusion may have come because of their resemblance to the cellar spiders, themselves getting a bad rap because their bites are practically harmless.  They’re just a short-lived fly whose larvae inhabit a variety of habitats from wetlands to lawns (where they both feed on and fertilize the grass).

EASTERN TAILED-BLUES are tiny butterflies with wingspans of an inch or less, but they’re tough enough to fly well into fall (four years ago, the BugLady saw one on November 4).  Like the Gray Hairstreak, the eye and tail on the hind wing are there to trick hungry birds into grabbing a wing, not an abdomen.  ‘Tis the season.

Go outside – there are still bugs!

Kate Redmond, The BugLady

Bug of the Week archives:
http://uwm.edu/field-station/category/bug-of-the-week/

Bug o’the Week – Zebra Jumping Spider

Bug o’the Week
by Kate Redmond

Zebra Jumping Spider

Greetings, BugFans,

The BugLady was moseying around her cottage, photographing doodlebug digs, when she spotted this very small (maybe ¼”) jumping spider with its prey.  It was on a sunny, south-facing wall – right where it was supposed to be!

Zebra spiders, aka Zebra jumpers (Salticus scenicus) are in the family Salticidae, the Jumping spiders.  Salticus is Latin for “dancing,” and scenicus is Greek for “theatrical” or “of a decorative place,” and refers to the spider’s flashy colors, which can look iridescent in the right light.  Thanks to BugFan Mike, as always, for the ID.  

We’re on a roll here, having recently introduced the non-native Clover weevil and the (probably) non-native American Copper butterfly.  The Zebra spider’s original range included Europe and western Asia.  It was first collected in North America (in Illinois) in 1933, and now it occupies most of the northern two-thirds of North America.  It’s an urban spider that loves the sun-warmed sides of buildings, but it’s also found away from human habitation, on bare rocks.

There’s some variation in pattern and color, and spiders that live in polluted urban areas may be all black.  Here’s a side view https://bugguide.net/node/view/1339892/bgimage.  Males have large, black jaws called chelicerae https://bugguide.net/node/view/2251820/bgimage.  Like all jumping spiders, Zebra spiders have appealing (some say cute) faces https://bugguide.net/node/view/171573/bgimage – jumping spiders have fan clubs and Facebook pages, largely because of the size and arrangement of their eyes. 

Jumping spiders have eight eyes, four facing forward and four facing upwards – they have depth perception, can judge distances, and can see in color.  Research suggests that when the lateral eyes on each side of those big median eyes pick up motion, they tell the median eyes where to look.  The four eyes on top of the head (cephalothorax) sense movement (helpful for dodging predators) and light. 

Zebra spiders don’t spin for their supper, they jump (and they can jump as far as four inches).  They stalk their prey brazenly by creeping directly at it, but if their prey is much larger than they are, they sneak up from behind.  Either way, they attach a silken drag line to the substrate as they leap, in case they miss or in case they and their prey tumble over the edge.  They bite, subdue, and eat their prey on the spot – they don’t wrap and store it because they have no web to store it in.  

What do they eat?  Various kinds of flies, including mosquitoes, are favorites https://bugguide.net/node/view/1811146/bgimage, but they go after insects that are much larger than they are https://bugguide.net/node/view/228175/bgimage and https://bugguide.net/node/view/383371/bgimage.  They find ants distasteful, but they will eat their fellow spiders https://bugguide.net/node/view/284184/bgimage.  

Females attract wandering males with pheromones, and courtship is visual – males dance, and the best dancers win.  Faint heart ne’er won fair maid.  He waves his front legs and chelicerae and displays his patterned abdomen (so that she doesn’t think he’s prey).  If she’s impressed (and scientists don’t know exactly which moves will light her fire), she’ll crouch and let him approach.  Sometimes males mistakenly display in front of other males, which results in ritualized battles that are won by the most aggressive fighter.

She produces a silken sac that holds 15 to 20 eggs and hides it under leaves or debris, and she guards it until the eggs have hatched https://bugguide.net/node/view/236348/bgimage.  The spiderlings stay with her until after their second molt, and then they disperse.  They overwinter as almost-mature spiders and may live for a year or two. 

Fun Facts about Zebra Spiders:

1)    Their jumps are driven not by muscles, but by hydraulic pressure – the spider increases the pressure of its haemolymph (blood), and that causes the 4th set of legs to straighten, which propels it off the ground.  The fact that the spines on a spider’s leg stand up as its legs straighten is considered proof of that explanation.

2)    Zebra and other jumping spiders can abseil/rappel down walls and rock faces.

3)    Cushions of hairs on the bottoms of their feet have adhesive qualities and allow them to walk on smooth, vertical surfaces. 

4)    Zebra jumpers operate during the day, and they retreat into silk shelters spun in crevices and under leaves and bark by night. 

5)    Vibrations (like buzzing wings) help Jumping spiders recognize their prey.

6)    If a Zebra spider accidentally comes inside, it might take up residence in the corner of a window.  No – it can’t bite us – not even a little bit.erved by a large jumping spider that was inside the car as she drove, alternately staring at her (jumping spiders are good at that) and then disappearing as she drove (that, too).

Kate Redmond, The BugLady

Bug of the Week archives:
http://uwm.edu/field-station/category/bug-of-the-week/

Bug o’the Week – Eastern Cicada-killer Wasp

Bug o’the Week
by Kate Redmond

The Clover Leaf Weevil and Other Tales

Howdy, BugFans,

A while back, BugFan Laurel shared this picture of a wasp that was photographed by her friend, Joel, who gave the BugLady permission to use it.  Thanks, Joel.

This is one large wasp.  In an article about it on the New Jersey Agricultural Experiment Station website, William Sciarappa writes “Few insects can compare with the alarm caused by Cicada Killer Wasps.”  At lengths up to 2” (females are larger than males – more about that later), it’s one of the largest in the country, so let’s get this out of the way up front.  No, the male can’t sting, though he does have a “pseudo-stinger,” and he sometimes “pseudo-stings” with it.  Yes, she can sting https://bugguide.net/node/view/807314/bgimage, but she’s a solitary rather than a social wasp, with no motivation to defend hearth and home, so you have to mistreat or step on her in order to get stung (or be a cicada).  Though there were a couple of dissenting voices, most sources agree that her bark is worse than her bite – on the Schmidt Insect Sting Pain Index, which rates pain on a scale of one to four, the Cicada killer’s sting is 0.5, lower than that of a honey bee.  One article called her “a marshmallow.”

Eastern Cicada-killer wasps (Sphecius speciosus) (speciosus means “showy” or “beautiful”) are in the Square-headed/Sand wasp family Crabronidae.  Four species in the genus (the Pacific, the Western, the Eastern, and the Caribbean Cicada-killers) combine to cover much of the Lower 48, south into Central America (there’s a South American Cicada-killer, and there are more species in the Old World).  They’re also called Giant cicada-killers, Cicada hawks, and Giant ground-hornets.  When the Northern giant hornet (formerly known as the Asian giant hornet/Murder hornet) arrived in the far Northwestern portions of the country, panicky folks in the East were mistaking cicada-killers for murder hornets. 

They prefer sunny edges, gardens, banks, berms, and disturbed spots with loose clay to well-drained sandy soil, close to trees that may harbor cicadas.  There are pictures of them using cracks in sidewalks and patio bricks, window boxes and planters as nest sites.  Here’s a nice collection of pictures of Eastern Cicada-killers at work and at play https://www.marylandbiodiversity.com/view/6434. 

Adults feed on tree sap and on nectar from flowers (and, apparently, peaches https://bugguide.net/node/view/820925/bgimage), and they’re considered pollinators.  Cicadas are the only food enjoyed by their larvae.  William Sciarappa again, “The female wasp strikes and stuns the Cicada which reacts with a loud shrieking buzz. Both of these very large insects tumble to the ground where the stinger is then utilized to paralyze the Cicada. This relatively huge prey is laboriously dragged up a tree or tall plant. The Cicada is often held upside down and straddled, after which the wasp takes off and glides home to the nest.”  If there’s no place for her to gain altitude, she will walk the cicada back to her nest tunnel.  The Western CKW has a preference for male cicadas and the Eastern and Caribbean CKWs for females.  She apparently locates her prey by sight rather than sound (female cicadas are silent).

A Cassin’s Flycatcher was observed flying out and intercepting prey-laden incoming female wasps and relieving them of their cicadas.  Skunks may dig up the larvae, and the odd spider may snag an adult.  A “velvet ant” (which is actually a kind of flightless female wasp) https://bugguide.net/node/view/2023193/bgimage, sneaks into her tunnel and lays an egg in an egg chamber (the ECKW leaves the chambers open until they’re fully provisioned), and the velvet ant larva parasitizes the ECKW pupa.

So – were ECKWs in hog heaven during the historic outbreak of Periodical cicadas this summer (https://uwm.edu/field-station/bug-of-the-week/the-cicadas-are-coming-a-tale-in-four-parts/)?  They were not – because of their phenology, they missed the show.  ECKWs target several genera of Dog-day cicadas that emerge after the Periodical cicadas are done.  The supply of Periodical cicadas is boom or bust, but the supply of Dog day cicadas is more dependable, so ECKWs are tuned into their cycles.  

Male ECKWs emerge when the cicadas start calling, and females emerge about a week later.  Males are very territorial, defending their turf against just about anything that enters it, deliberately crashing into intruding insects, while constantly trying to attract females.  They inspect and follow people fearlessly but will fly off if swatted at.  They communicate by buzzing their wings, warning away other males (the largest males make the loudest buzz), and buzzing may also be part of courtship.  They gather in groups (mating aggregations or leks), scouting areas where females might be and duking it out in mid-air.  Females call to males using pheromones. 

They mate on the ground https://bugguide.net/node/view/374679/bgimage https://bugguide.net/node/view/206285/bgimage and then take to the air.  The female “leads, but his wing beats help power the flight, even though they’re facing opposite directions. 

Females dig burrows that are 10” to 20” deep and 30” to 70” long with as many as a dozen egg chambers.  She leaves a U-shaped trench of soil near the entrance, to the dismay of lawn-owners and golf course maintenance crews (the best defense is a well-watered, dense, healthy turfgrass).  She loosens the dirt with her jaws and kicks it out with her hind legs, eventually displacing, said one source, several pounds of soil or, said another source, 100 cubic inches of dirt.  Even though they’re not social, several females may share a burrow, each excavating her own set of egg chambers.  She provisions each with a cicada or three, lays an egg on a cicada leg, seals the cell, and departs https://bugguide.net/node/view/2391638/bgimage, and she may handle 30 or more cicadas in her lifetime.  The eggs hatch, and the larva eats its cicada in a specific order that keeps the cicada alive until the larva is ready to pupate https://bugguide.net/node/view/1328710/bgimage. 

They overwinter as mature larvae in a cocoon, pupate, and dig out of the tunnel as adults in late spring.  Their flight period is about two months; males die after mating, and females die after egg-laying. 

Female ECKWs have a superpower, but the BugLady found two different explanations of it. They have, as they lay their eggs, the ability to determine whether the egg will be male or female, or possibly, an awareness of the egg’s gender.  Males may mate several times, but females only mate once, so she stores his bodily fluid in a receptacle called a spermatheca, meting it out as needed as she gradually fills tunnels and egg chambers.  According to one version, if she does not fertilize the egg, the larva will be a male, and if she does, the larva will be female.  According to the second version, the female somehow senses whether the egg she’s about to lay is male or female.  In either case, males are allotted a single cicada, but the eventual females are provisioned with two or three.  Females end up twice as large as males, but they have the job of toting around cicadas that are larger and bulkier than they are.  And – Mother Wasp also ensures that there are more females than males in the population.    

Ain’t Nature Grand!

On a different note: After reading the story of the spider that went to the laundromat in last week’s BOITW, two BugFans shared their own experiences with car spiders. One keeps the outside of her car a little dirty, so the spiders have something to grip; the other BugFan (not-so-much of a spider fan) was unnerved by a large jumping spider that was inside the car as she drove, alternately staring at her (jumping spiders are good at that) and then disappearing as she drove (that, too).

Kate Redmond, The BugLady

Bug of the Week archives:
http://uwm.edu/field-station/category/bug-of-the-week/

Bug o’the Week – The Clover Leaf Weevil and Other Tales

Bug o’the Weeku
by Kate Redmond

The Clover Leaf Weevil and Other Tales

Howdy, BugFans,

The BugLady has been playing outside, and she had trouble coming in long enough to write these stories.

STORY #1 – THE CLOVER LEAF WEEVIL.  The BugLady took a few “throw-away shots” of this little (3/8” long) beetle as it crawled along a boardwalk in a wetland, and she made a few inaccurate guesses about its identity, but the sun was bright and she couldn’t really see the image on the screen, and then she and the beetle went their separate ways.  Turned out to be a completely different beetle than she thought, one that apparently took a wrong turn at the start of the boardwalk.  

It was a weevil https://bugguide.net/node/view/859710/bgimage, a weevil that has gone through more than a dozen combinations and permutations of scientific names since it was first described in 1763 (“A rose by any other name….”) and that can still be found under multiple names in the contemporary literature.  Some of the names resulted when the species was described and named by one person, but had already been described and named by another (18th century entomologists received specimens from contacts all over the world, and communication among them was slow).  Other name changes happened when the family or subfamily or genus of the weevil was revised (and some of those changes were not embraced by others in the field).  The BugLady gets the feeling that the dust has not settled on this weevil’s name. 

The Clover, or Sandy, Leaf Weevil (we’ll go with Donus zoilus) is in the Snout/Bark beetle family Curculionidae.  It’s the only member of its genus in our area, but there are a lot more genus members globally, and it’s not from around here.  It was originally found in the “Palearctic realm” – Europe and Asia between the Arctic and North Africa/India.  With a little help from its friends (us), it jumped the Big Pond and came to live in the Nearctic realm (North America between the Arctic and Mexico).  It made its North American debut in Quebec in 1853, and now it’s present over about three-quarters of the country.  . 

Here are some glamour shots: https://bugguide.net/node/view/141240/bgimage, https://bugguide.net/node/view/859709/bgimage. 

Its habitat is listed as grasslands, clearings, roadsides, and edges, and while adults may feed on a few plants that are not in the Pea family (the BugLady can recall no members of the Pea family along that boardwalk), the raison d’être for both adults and larvaeis eating agricultural clovers, especially alfalfa.  Larval host plants include alfalfa, red, white, crimson, and alsike clovers, and sweet clovers (sweet clovers (the Devil Incarnate), of which they may consume as much as they can hold). 

Both adult and larval Clover leaf weevils feed at night or on cloudy days, and shelter on/in the ground in the sunlight.  The larvae/grubs https://bugguide.net/node/view/1535920 make small holes in the leaves.  Most sources said that unless they occur in high numbers, they’re not a major crop pest (unlike the much smaller, Alfalfa leaf weevil).  The grubs are parasitized by the larvae of this lovely little ichneumon wasp https://bugguide.net/node/view/1152272.

There’s only one brood per year – females place eggs in and around the host plants in fall.  Most eggs hatch then and the larvae overwinter, feeding when it’s warm enough and resting when it’s not, then pupating https://bugguide.net/node/view/1535924 and becoming adults in spring.  Any eggs that overwinter hatch in spring.  Newly-emerged adults feed and then aestivate (suspend operations) for part of the summer, reactivating and laying eggs in fall https://bugguide.net/node/view/1655976/bgimage.  Larvae chew on plants in spring, and adults chew on plants in fall. 

STORY #2 – RECENT SPIDER ADVENTURE.  The BugLady headed to the laundromat the other day.  She got a few miles down the road and noticed (belatedly) a Cross Orbweaver on a strand of web on the inside of the driver’s side window (“along came a spider and sat down beside her…”).  She found an uninhabited side road and pulled way over to the left, so the side of the car was in grass, opened the window and nudged the spider out, hoping to move it away from the car.  When she got to the laundromat, the windblown spider was curled tight, clinging to the side of the car below the mirror.  It stayed there while the laundry went around, and then held on for the ride home.  The BugLady lifted her off with a leafy twig, and the spider recovered on the porch rail.  Spiders are tough! 

STORY #3 – AN EXUBERANCE OF DRAGONFLIES.  We experienced a wonderful, three-day dragonfly migration from August 30 into September 1, and in the run-up to that migration, the BugLady enjoyed some amazing walks through big feeding swarms, with darners cruising past, inches away.  As she went out to the hawk tower on Sunday, darners and saddlebags were in the air everywhere, with even more jumping up from the grass as she passed.  When she scanned for incoming hawks, the view through her binoculars was dragonflies as far out as she could see, in all directions.  Magic!  Abruptly, at 1:00 PM, the wind shifted a bit and it was over, and only the stragglers remained. 

Go outside, look at bugs!!

Kate Redmond, The BugLady

Bug of the Week archives:
http://uwm.edu/field-station/category/bug-of-the-week/

Bug o’the Week – Black Horse Fly redo

Bug o’the Week
by Kate Redmond

Black Horse Fly redo

Howdy, BugFans,

The BugLady has gotten a few reports of these magnificent flies recently, so here’s an episode from 2018, with some new words and thoughts and links added.

People often ask the BugLady what her favorite bug is, and although there’s a crowded field for second place, the Tiger Swallowtail butterfly is the hands-down winner.  Most Impressive Bug?  The Black horse fly (Tabanus atratus) (family Tabanidae) certainly ranks high on that list.  It is one, imposing horsefly, and although she knows that it’s (probably) not going to pursue her (they generally stalk non-human mammals), just seeing one gives her a bit of a start.  We visited the Black horse fly in the distant past, very briefly, one of an array of flies, and it’s time to fill in some gaps in its biography.  This fly is not the tiny, humpbacked Black fly that lives near rivers and torments all comers https://uwm.edu/field-station/bug-of-the-week/black-fly-the-bug-the-legend/. 

Yes, there are larger flies in the neighborhood – some of the robber flies, for example, are longer – but they lack the heft of this fly.  Even the official measurement of 20 to 28 mm (an inch-ish) doesn’t adequately communicate it.  As one bugguide.net correspondent put it: “This is the largest fly I have ever seen, I actually saw two of these at two different locations on the same day. I am guessing it is a horsefly of some sort. A handful of these things ought to be able to carry a horse as a ‘to-go’ meal!”  And as another bugguide.net correspondent said, “I’m assuming this is a female Tabanus atratus? First time I’ve seen one. Not sure I want to see another.”  And as Jess Adams wrote in his blog “Long Leggedy Beasties,” “I’m not sure if they are called horse flies because they feed on horses or because they are the size of horses….”

Indeed, it’s hard to believe that these huge flies (https://bugguide.net/node/view/1114670/bgimage) are not the biggest horseflies on the continent, but they come in a close second to the American horsefly https://bugguide.net/node/view/117708/bgimage, which may hold the World Title.   

“Atratus” means “clothed in black,” and one of the common names for this fly is the Mourning fly.  Adults are variously dark gray/black/brownish-purple, with equally dark wings, dark eyes, and antennae that are hooked https://bugguide.net/node/view/1890081/bgimage (in case you still were unsure of your ID).  Males have wrap-around (holoptic) eyes that touch at the top of the head https://bugguide.net/node/view/1494235/bgimage, and females’ eyes are separated (dichoptic) https://bugguide.net/node/view/827314/bgimage.   

It’s been suggested that they’re the infamous “blue-tailed fly” from the folk song “Jimmy Crack Corn” https://bugguide.net/node/view/367846/bgimage (the BugLady expected to find a bunch of common names for this fly, most of them profane, but she didn’t come across any).  They can be a challenge to photograph because their velvety, black color sucks up the light.  Check the phenomenal, final three pictures on the Maryland Biodiversity website https://www.marylandbiodiversity.com/view/9571. 

Their larvae are pale with dark bands https://bugguide.net/node/view/677968 and may be twice as long as their elders when mature.  They have pointy mouthparts that, like their elders’, can pack quite a punch. 

Though it’s been recorded throughout the Lower 48, the Black horse fly is mostly found east of the Rockies.  Its larvae live in wet/damp places at the edges of wetlands, and the adults are generally found within a mile or so of the ponds they grew up in. 

Females lay their eggs in mounds on wet ground or on sedges and other vegetation above water, and they may deposit three or four such masses https://bugguide.net/node/view/1014993/bgimage (male Black horse flies don’t live for long).  The newly-hatched larvae drop down and dig into the detritus or mud, and they spend two years as larvae. 

According to Werner Marchand in the Monographs of the Rockefeller Institute for Medical Research (1920), “Walsh found his aquatic larvae, on many occasions, ‘amongst floating ‘rejectamenta.’  On one occasion, he found six or seven specimens in the interior of a floating log so soft and rotten that it could be cut like cheese.”  He goes on to say that “when handled, the larva is, according to Walsh, ‘very vigorous and restless,’ and burrows with great strength between the fingers, and even on a smooth table, walks as fast as any ordinary caterpillar, backwards or forward; when placed in a vessel of water it swims vigorously, twice the length of its body at every stroke...” 

“Rejectamenta” – the BugLady’s new favorite word!

Marchand writes that the larvae can produce sound “…the crackling noise was freely produced by full-grown Tabanus atrata larvae, and … was chiefly heard when the larvae were disturbed and defending themselves with their sharp mandibles.  The coincidence of the two phenomena was so close that I am bound to assume that the sound was produced by means of the mandibles.”

The larvae climb up onto drier ground to pupate in the soil.  Marchand says that “the pupa state lasts but a few days, and before the emergence of the fly the pupa is pushed to the surface of the ground by means of the bristles and thorns of the abdomen, with bending movements of the body.”  For more about what happens in a pupal case, see http://uwm.edu/field-station/pupal-cases/.

Much of what is written about Black horse flies concerns their food and feeding habits.  The larvae are active predators.  Marchand again: “On September 2, 1863, he found a nearly full-grown larva among floating rejectamenta, and between that date and September 23, this larva devoured ‘the mollusks of eleven univalves’ (genus Planorbus) from one-half to three-fourths of an inch in diameter; and on three separate occasions observed it work its way into the mouth of the shell.”  They eat other aquatic invertebrates, too, and small vertebrates, and even their Tabanid brethren.  Jones and Anthony, in The Tabanidae (Diptera) of Florida write “medium to large-size larvae of Tabanus atrata are extremely aggressive.  When two or more are placed in the same container, only a short time usually elapses before all are dead except one.  The survivor will feed on the victim if hungry, but generally it appears that a larva kills to avoid being killed.” 

Like mosquitoes, female tabanids need a blood meal in order to maximize egg production.  Both males and females feed on nectar from flowers (he lacks her piercing mouthparts), but when she is in reproductive mode, a female will stalk livestock and other large, dark mammals by their movement and by their CO2 trail.  She punctures her victim’s skin with a pretty sophisticated set of blades (modified mandibles and maxillae) and is classed as a sanguivore – more specifically, she is a telmophage, because she laps up the resulting pool of blood instead of sucking it (unlike mosquitoes, who are “vessel feeders” or solenophages that employ a “syringe and pump”).  Got it?  

Although humans are generally not targets, a bite is, apparently, unforgettable.  When present in numbers, these flies can be a problem for livestock due to blood loss, distress, and potential disease transmission. 

Several resources pointed out something that the BugLady had never really thought about before – that being a sanguivore, getting a meal by puncturing an animal that is larger and that takes exception to being punctured, is a dangerous way to make a living.  The blood is, as one researcher points out, “not freely given,” and a potential victim may simply swat its tormentor away or may eat it.  The BugLady once went on a canoe trip on Wisconsin’s Oconto River during which she was accompanied by clouds of deer flies and learned to swat them without breaking stroke, and after nine hours on the water, there was a layer of dead deer flies over the bottom of the canoe (our blood was not freely given, either) (the 50 yards of whitewater just before the pull-out spot were pretty memorable, too). 

Another down-side of blood-feeding is that depending on the body temperature of the “pierce-ee,” the cold-blooded piercer is courting temperature shock by ingesting a substance that is much warmer than it is. 

The “take-home” is that sanguivores need to do their work in a hurry (solenophages tend to get in and out more quickly and quietly than telmophages), and that the nutrition received needs to be worth the energy – and risk – required to extract it. 

Kate Redmond, The BugLady

Bug of the Week archives:
http://uwm.edu/field-station/category/bug-of-the-week/

Bug o’the Week – Summer Sights

Bug o’the Week
by Kate Redmond

Summer Sights

Greetings, BugFans,

The BugLady has been scouring the landscape and aiming her camera at anything that will sit still for it (and some that won’t).  And (without going too overboard on dragonflies and damselflies), here are some of her bug adventures.

LEAFCUTTER BEE – ah, the one that got away.  The BugLady saw a lump on a boardwalk in front of her and automatically aimed her camera at it (a long lens is a good substitute for a pair of binoculars).  The lump – a leafcutter bee – flew off after one, out-of-focus shot.  The bee had paused while she was cutting and collecting pieces of vegetation to line the tunnel and chambers where she’ll lay her eggs (here’s one caught in the act https://bugguide.net/node/view/2150206/bgimage). 

JAPANESE BEETLE – lots of the vegetation that the BugLady sees these days is pockmarked with small holes – evidence of feeding by Japanese beetles (of course, she’s also been seeing conspicuous, beetle ménages a trois on the tops of those leaves, too).  Japanese beetles made their North American debut in New Jersey in 1916, and their menu now includes more than 350 plant species.  But – they are a handsome beetle!  

WATER STRIDERS create art wherever they go. 

APPALACHIAN BROWN BUTTERFLY (probably) (the part of the hindwing that has the squiggly line that helps distinguish the Eyed Brown from the Appalachian Brown is gone).  Life in the wild isn’t all beer and skittles.  The chunks missing from this butterfly’s wings suggest that a bird chased it and that most of the butterfly got away.

POWDERED DANCER – in an episode a month ago, the BugLady lamented that the river was so high and fast that Powdered Dancers couldn’t find any aquatic vegetation to oviposit in.  A dryer spell revealed some weed patches, and the dancers hopped right onboard.

EASTERN PONDHAWK DRAGONFLY – this male Eastern Pondhawk was hugging the cattail stalk, a posture that’s not characteristic of this usually-horizontal species.  Turns out that it had captured a Violet/Variable Dancer damselfly and was holding it closely between its body and the cattail. 

CRAB SPIDER – what would a summer summary be without one of the BugLady’s favorite spiders, the Crab spider?  Where’s Waldo?  Bonus points if you know the name of the plant. 

HONEY BEE WITH APHIDS – it’s not surprising to see yellowjackets browsing among herds of water lily aphids – adult yellowjackets are (mostly) vegetarians, but they collect, masticate, and regurgitate small insects for their larvae.  Honey bees are hard-core vegans, so what’s going on here? 

Aphids overeat.  They have to – the plant sap they suck in has very low concentrations of sugars and proteins, so they need to process a lot of it in order to get enough calories.  Sap comes out of the plant under pressure, which forces the sap through the aphid smartly, and the extra liquids (in the form of a sweet substance called honeydew), exit to the rear of the aphid (or it would explode).  Honeydew drops onto the surrounding leaves and attracts other insects that harvest it.  The bee is no threat to the aphids, she’s just collecting honeydew.  

Fun Fact – according to Master beekeeper Rusty Burlew, writing in her blog “Honey Bee Suite, “The bees treat the substance like nectar so it is often mixed together with the nectar from flowers. As such, it is not really noticeable in the finished honey. Honey made almost exclusively from honeydew is known as honeydew honey, forest honey, bug honey, flea honey, or tree honey. Sometimes it is named after its primary component, such as pine honey, fir honey, oak honey, etc. It is generally dark, strongly flavored, less acidic, and less sweet than floral honey.”

EASTERN AMBERWING – at barely an inch long, this improbably-colored dragonfly is one of our flashiest.

MOSQUITOES – Mosquito Control 101: “get rid of standing water in your yard!”  Check.  But, the BugLady has a bird bath (her “vintage” childhood saucer sled) that she washes out and refills at least once a week (or so she thought).  She was surprised the other day to see a whole mess of mosquito “wigglers” (larvae) in the water.  Worse, they probably were the small-but-mighty Floodwater mosquitoes that can make August miserable because they emerge in Biblical numbers, and because they seem to be biting with one end even before the other end has fully landed.  They develop at warp speed – a week from egg to wiggler, and another week from wiggler to adult.  Get rid of standing water in your yard.  Check.

SCORPIONFLIES are odd-looking insects from a whole order of odd-looking insects (Mecoptera).  This guy is in the Common scorpionfly family Panorpidae and in the genus Panorpa (which is a corruption of the Greek word for “locust”).  The appendage at the end of the male’s abdomen explains its name, but these are harmless insects, fore and aft.  One site mentioned they are wary and hard to photograph.  Amen!

Panorpa uses chewing mouthparts at the tip of its elongated rostrum/snout to eat dead and dying insects, and it may liberate insects from spider webs (and sometimes the spider, too).  It is also said to eat some nectar and rotting fruits.

He courts by releasing pheromones to attract her, quivering his wings when she comes near, and then offering a gift – a dead insect, or maybe some gelatinous goo manufactured in his salivary gland.  He shares bodily fluids with her as she eats.

CAROLINA LOCUST – what a lovely, chunky little nymph! 

AUTUMN MEADOWHAWK – the dragonfly scene changes after mid-summer, with the early clubtails, emeralds, corporals, whitefaces, and skimmers being replaced by darners, saddlebags and a handful of meadowhawk species.  This newly-minted (teneral) Autumn Meadowhawk has just left its watery nursery on its way to becoming – for the next six weeks or so – a creature of the air. 

KATYDID NYMPH – the BugLady was photographing leafcutter bees that were visiting birdsfoot trefoil flowers (birdsfoot trefoil is a non-native member of the pea family that was introduced for animal fodder and erosion control and that can become invasive in grasslands.  There’s probably some blooming along a road edge near you).  She noticed that when the bees approached one particular flower, they reversed course and didn’t land, and when she checked she found the tiniest katydid nymph she has ever seen.  This one will grow up considerably to be a 1 ½” to 2” long Fork-tailed bush katydid (or somebody else in the genus Scudderia) https://bugguide.net/node/view/2164189/bgimage.  How do you find bush katydids?  The “Listening to Insects” website advises us to “Watch for a leaf that moves on its own, or a leaf with antennae.”  They are a favorite of Great golden digger wasps, which collect and cache them for their eventual larvae, and another website said “this is what bird food looks like.” 

The BugLady found a recording of their call.  They don’t say “Katy-did, Katy-didn’t;” they say “tsp” or “pffft,” and they don’t say it very loudly.  Bush Katydids are busiest at night, when their long, highly sensory antennae help them to find their way around.  Although adult females are equipped with a wicked-looking ovipositor, they don’t sting, but they do nip if you handle them wrong.  Memorably, it’s said.   

Go outside, look at bugs!

Kate Redmond, The BugLady

Bug of the Week archives:
http://uwm.edu/field-station/category/bug-of-the-week/

Bug o’the Week – Imperial Moth

Bug o’the Week
by Kate Redmond

Imperial Moth

Greetings, BugFans,

Well, the BugLady completely zoned about National Moth Week last week, so we are celebrating it now, tardily (but hey, every week is Moth Week).

BugFan Mary emailed to say that she found a deceased Imperial Moth, and did the BugLady want to see it?  Oh yes!  Mary was keeping it in a plastic container, and by the time the BugLady connected with her, the moth was getting pretty fragrant.  The BugLady has sneaked pictures of appropriately-posed dead insects into a few BOTW episodes in the past, but none as obviously dead as this one.

Imperial moths are members of the Giant Silkworm/Royal Moth family Saturniidae, a group of often-large and often-spectacular moths with wingspreads up to 6.”  Saturniidae is divided into three subfamilies – the Royal moths, the Buck and Io moths https://bugguide.net/node/view/1670029/bgimage and https://bugguide.net/node/view/1768803/bgimage, and the Silk moths like the Cecropia, Polyphemus, and Luna moths – here’s a BOTW about the Silk moth subfamily https://uwm.edu/field-station/bug-of-the-week/giant-silk-moths-family-saturnidae/. 

[Slight detour for a gratuitous and awesome caterpillar in the Royal moth subfamily.  The Regal/Royal Walnut moth caterpillar even has its own name, the Hickory Horned Devil.  Here’s a nice series of pictures https://bugguide.net/node/view/11016/bgimage.] 

Female Saturniid moths “call” males by releasing pheromones.  Using their feathery antennae, the males can detect these chemicals from several miles away.

Saturniids produce large, spectacular, bumpy/knobbed/spiny/hairy caterpillars.  Most of the caterpillars feed, sometimes destructively, on leaves of a variety of woody plants (a few on grasses), but adults don’t feed at all, fueled, as one source said, only by what they ate as caterpillars. 

Their caterpillars protect themselves variously with camouflage (often, finding their frass (poop) is the first clue that they’re around), with stinging hairs, by producing clicking sounds, or by vomiting when attacked (it’s theorized that their aposematic (warning) coloration announces the upcoming vomit).  Many moths have eyespots on their wings to spook predators.  Saturniids do make silk, but it’s not particularly harvestable – the silkworm moths whose silk is woven into fabric are in a different family.   

For a variety of reasons, Saturniid populations are shrinking.  The usual suspects – habitat change and pesticides – are joined by high intensity street lights that interrupt mating (females tend to stay in the vicinity of their natal trees, but males are far-ranging and easily distracted by lights), and by overzealous introduction of parasitic flies and wasps meant to control the Spongy (formerly Gypsy) moth.  These non-native parasitoids, alas, show a decided affinity for the silk moths and not enough of an interest in Spongy moths.  Hopefully, we’re doing a better job at screening potential biological control species these days.  

Anyway, the IMPERIAL MOTH (Eacles imperialis), aka the Great Plane Tree moth and the Yellow Emperor, is in the Royal moth subfamily Ceratocampinae (which is Greek for “horned caterpillar”) and is one of two (or maybe more) species in its genus in the US, and (maybe) the only one in the East.  Variability in the color of Imperial moths and caterpillars https://www.marylandbiodiversity.com/view/335 (be sure to scroll all the way down) has led to some taxonomic tussles – there are regional morphs or color forms, subspecies, and sibling species.  Sibling species are evolution in action – a species that is splitting.  These are closely-related organisms whose forms look pretty much alike to us, but not to each other, so they don’t mate (reproductive isolation).  Next step – the development of more distinctive physical or behavioral characteristics, and finally, an official species nod.  One subspecies, the Pine Imperial moth (Eacles imperialis pini) occurs on both sides of the border from northern Michigan to Vermont, restricts its diet to conifer needles, and has been considered a separate species by some.  DNA barcoding will ride to the rescue.   

Imperial moths are primarily found in deciduous and mixed woodlands and barrens east of the Great Plains from Canada to Florida to Texas, and south to Argentina, but their historic range extended farther north than it does today.  Moths have wingspans of 4” to 5” https://bugguide.net/node/view/2038089/bgimage, with females slightly larger than males, and males more heavily marked than females.  Based on the two dark spots on the underside of the end of this moth’s abdomen (and its feathery antennae), it’s a male.  Caterpillars may measure up to 4.” 

Females call from the treetops at night and romance ensues https://bugguide.net/node/view/1395835/bgimage.  They place their eggs, singly or in small batches https://bugguide.net/node/view/802928/bgimage , on the upper and lower surfaces of leaves, laying several hundred in all.  Caterpillars feed alone, and when they’ve eaten enough, crawl down the tree trunk, dig a hole, and create a pupal cell underground.  They overwinter there, and the pupa emerges by backing up and out of its cell, onto the ground, early the next summer. 

The list of caterpillar host trees is long and includes oak, hickory, walnut, sycamore, basswood, maple, elm, beech, hornbeam, birch, some conifers and more.  In his Caterpillars of Eastern North America, Wagner says that “caterpillars feed by locking onto vegetation with their powerful anal prolegs (https://bugguide.net/node/view/1134273/bgimage) and pulling leaves or needles back over the body.”  Although females lay lots of eggs, Imperial moths are not common.  The moths are sedentary by day, blending into tree trunks and forest litter but are eaten by bats at night, and the caterpillars provide a tasty meal for birds, which find them as they feed by day on leaf surfaces, for mammals (including armadillos, which dig them out of their pupal cells), and for other insects.  Including parasitic flies.  Unlike some of their cousins, Imperial moths have no chemical defenses or stinging hairs, but young caterpillars, bearing long protuberances (scoli) on their thoraxes, wave their front ends back and forth to bluff predators https://bugguide.net/node/view/10760/bgimage.   

Thanks, Mary,

Kate Redmond, The BugLady

Bug of the Week archives:
http://uwm.edu/field-station/category/bug-of-the-week/

Bug o’the Week – Rosinweed Moth

Bug o’the Week
by Kate Redmond

Rosinweed Moth

Howdy, BugFans,

First off, today’s vocabulary word is “microlep” (short for “microlepidoptera”).  What’s a microlep?  The (somewhat squishy) term applies to moths with a wingspan under 20mm (about ¾”).  It’s not a taxonomic or a lifestyle designation – there are microleps across a bunch of different moth families, and they make their livings in a variety of ways – it’s strictly about size.

Rosinweed moths (Tebenna silphiella) (what a little gem!) are a not-well-studied species in a not-well-studied genus in a not-well-studied family, Choreutidae, the Metalmark Moths, a group that (of course) needs revision and that historically has been bounced around, taxonomically.  And, the website microleps.org tells us that “The large Tebenna spp., including T. silphiella, represent an array in which species delineations appear to be unresolved.”  Most family members have wingspans under a half-inch, but those wings may be decorated with spots made of silvery/metallic scales https://bugguide.net/node/view/1169370/bgpage, https://bugguide.net/node/view/1681270/bgimage.  Choreutis comes from a Greek word meaning “dancer” – the moths fly by day, and the “dancing” refers to the jerky movements they often make with their bodies and wings as they move around on flowers.  

Choreutid caterpillars skeletonize the undersides of leaves in groups, immediately after hatching, and solo, as they get older.  Many species spin a loose web over themselves, and their frass collects in this net (remember – they’re under the leaf).  About caterpillars in the related genus Brenthia (a mostly Asian and African genus), researcher Jadranka Rota says “Larvae of all four Brenthia species that I have observed chew a roughly circular ‘escape hatch’ – a wormhole – somewhere in their feeding shelter. When resting, they sit with their head next to the hole. If disturbed, larvae dash through the wormhole to the other side of the leaf…… After a little while, they wriggle through the opening backwards to their original position.”  Another researcher hypothesizes that the caterpillars receive sensory clues via the webbing. 

Some Metalmark moths have a Superpower – more about that in a sec.

As the name suggests, the host plant of Rosinweed moths is Rosinweed (Silphium integrifolium), a prairie plant with stiff, gritty leaves https://illinoiswildflowers.info/prairie/plantx/rosinweedx.htm.  They feed on leaves near the top of the plant; scroll down for a picture of caterpillars feeding https://mothphotographersgroup.msstate.edu/species.php?hodges=2642. 

Bugguide.net lists the range of Rosinweed moths as the prairies and meadows of the Central US – Wisconsin, Michigan, Illinois, Iowa, Missouri, Arkansas, and Kentucky, and other sources add Colorado.  There are two generations per year. 

OK – the Superpower.

In many parts of the family’s worldwide range, their top predators are the jumping spiders that hang out on the leaves with them.  What’s a moth to do?  Answer – If you can’t beat ‘em, join ‘em. 

Jumping spiders hone in on a wide variety of prey, large and small, and they’re not shy about eating other jumping spiders, no matter the size, so mimicking a jumping spider certainly isn’t a Get Out of Jail Free card.  But it turns out that the spots and stripes on the wings of many Metalmark moths resemble a jumping spider (if you squint), and the moth’s posture, displays, and movements reinforce that.  In experiments, Brentia moths survived being caged with jumping spiders more often than similarly-sized, non-Choreutid moths did (unless researchers painted over the eyespots on their wings).  Often, the jumping spiders (even with their great eyesight) would respond to the moth’s antics with the kinds of leg-waving territorial displays that they reserve for other jumping spiders of the same species.  If the moth was bigger than the spider, the spider may even have been intimidated by the moth. 

Here’s an American Brenthia, the Peacock Brenthia https://bugguide.net/node/view/1801949/bgimage and a video of a Metalmark moth in action – https://www.reddit.com/r/Awwducational/comments/ryq98f/metalmark_moths_have_evolved_eyespots_on_their/?rdt=48206.

Researchers also suspect that looking like a jumping spider discourages some of the spiders’ predators from going after the moths.  Some species hide by camouflage or by mimicking species that are aggressive or toxic.  Metalmark moths confuse the spider with an uncommon, “In your face” strategy called “predator mimicry,” but it turns out that jumping spider mimicry is also in the playbooks of a few small flies and planthoppers, which suggests that the spiders are driving the evolution of their prey.

For more information see https://askabiologist.asu.edu/plosable/prey-as-predator.

Kate Redmond, The BugLady

Bug of the Week archives:
http://uwm.edu/field-station/category/bug-of-the-week/

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